Mechanical Doppler signal generation device based on single 360-degree helical blade and speed measurement method thereof

Abstract

The invention discloses a mechanical Doppler signal generation device based on a single 360-degree spiral blade and a speed measurement method thereof. The device comprises the single 360-degree spiral blade, a supporting rod, a base and an ultrasonic probe. A 360-degree single-piece spiral blade is arranged on the base through a supporting rod, a motor drives the 360-degree single-piece spiral blade to rotate, and an ultrasonic probe is arranged right in front of a sector of the 360-degree single-piece spiral blade and used for transmitting and receiving ultrasonic signals. The device is simple in composition, small in size, high in speed, capable of conveniently generating adjustable high-quality coopler echo signals, capable of effectively reducing cost, quite suitable for teaching and scientific research and capable of conveniently detecting an ultrasonic Doppler velocity measurement system.

Description

Technical Field

[0001] The invention belongs to the field of ultrasonic application, utilizes the motion characteristics of a single spiral blade to generate a stable mechanical Doppler signal, converts the angular velocity into a linear velocity that is easy to measure, and is used to verify the accuracy of an ultrasonic Doppler measurement system. Background Art

[0002] When the sound wave source moves, the measured frequency has a certain change compared to the actual frequency emitted by the wave source. The direction and speed of the wave source movement determine the magnitude of the frequency shift. This phenomenon is called the Doppler effect. The Doppler effect can be used to measure the speed of a moving object.

[0003] Existing devices for generating mechanical Doppler signals have complex structures, mostly using linear simple harmonic motion, large size, and are limited by travel distance. They cannot maintain uniform motion for a long time, resulting in unstable Doppler signals, which is not convenient for ultrasonic Doppler measurement systems to collect and measure.

[0004] The existing Doppler signal generating device has a limited movement distance and is difficult to increase in speed, resulting in a very limited frequency shift of the generated Doppler signal, which is not comprehensive enough when testing the ultrasonic Doppler measurement system.

[0005] 360 degrees

[0006] The present invention aims to avoid the shortcomings of the above-mentioned prior art and provide a mechanical Doppler signal generating device based on a single spiral blade and a speed measurement method thereof, so as to generate a stable and controllable mechanical doppler ultrasonic signal, thereby fully verifying the accuracy of the ultrasonic Doppler speed measurement system.

[0007] The present invention solves the technical problem by adopting the following technical solution:

[0008] The invention discloses a mechanical Doppler signal generating device based on a single 360-degree spiral blade, which comprises: a single 360-degree spiral blade, a support rod, a base, and an ultrasonic probe;

[0009] A single 360-degree spiral blade is arranged on the base through a support rod, and the single 360-degree spiral blade is driven by a motor to rotate;

[0010] An ultrasonic probe is arranged directly in front of the fan surface of the 360-degree single-piece spiral blade for transmitting and receiving ultrasonic signals.

[0011] The speed measurement method of the mechanical Doppler signal generating device based on the single-piece 360-degree spiral blade of the present invention is characterized in that it is carried out according to the following steps:

[0012] Step 1: Use a motor to control the rotation of a single 360-degree spiral blade, and after the speed of the single 360-degree spiral blade is stable, use an ultrasonic probe to transmit a frequency of Ultrasonic signal;

[0013] Step 2: According to the Doppler effect, the single 360-degree spiral blade receives a frequency of After the ultrasonic signal is generated, the frequency is The echo signal;

[0014] Step 3: According to the Doppler effect, the frequency received by the ultrasonic probe after being reflected by a single 360-degree spiral blade is The doopler echo signal;

[0015] Step 4: Analyze and process the doopler echo signal to obtain the rotation angular velocity of the single 360-degree spiral fan blade;

[0016] Step 4.1: Calculate the Doppler shift using equation (1): :

[0017] (1)

[0018] Step 4.2: Use equation (2) to construct the Doppler frequency shift With a single 360 ​​degree spiral blade linear speed The relationship is:

[0019] (2)

[0020] In formula (2), is the propagation speed of ultrasonic wave;

[0021] Step 4.3: Use formula (3) to calculate the rotation speed of a single 360-degree spiral blade. Horizontal displacement :

[0022] (3)

[0023] In formula (3), is the pitch of a single 360-degree spiral blade; The rotation angle of a single 360-degree spiral blade;

[0024] Step 4.4: Use equation (4) to construct the angular velocity of a single 360-degree spiral blade: With line speed The relationship between: (4)

[0025] In formula (4), Single piece 360 ​​degree spiral blade rotation Time taken;

[0026] Step 4.5: Use formula (5) to obtain the angular velocity of a single 360-degree spiral blade: :

[0027] (5)

[0028] Step 5: After using the motor to adjust the single 360-degree spiral fan blade to reach different rotation speeds, return to step 1 and execute sequentially, thereby realizing the speed measurement of the single 360-degree spiral blade based on the Doppler effect.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] 1. Compared with the traditional device for generating mechanical doopler ultrasonic signals, the present invention has a simpler structure and effectively reduces the cost.

[0031] 2. The single 360-degree spiral blade of the present invention can maintain a long-term uniform rotation speed and the speed is controllable. By emitting ultrasonic waves to it through an ultrasonic probe, a stable and adjustable mechanical doopler ultrasonic signal can be generated without replacing the ultrasonic probe. Compared with the traditional device for generating mechanical doopler ultrasonic signals, the present invention effectively improves the quality and spectrum range of the generated mechanical doopler ultrasonic signal.

[0032] 3. According to the structural characteristics and rotation characteristics of the single-piece 360-degree spiral blade, the present invention can convert the angular velocity of rotation into a linear velocity that is convenient for the ultrasonic Doppler measurement system to measure, thereby facilitating the verification of the reliability of the ultrasonic Doppler measurement system. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a structural diagram of a single 360-degree spiral blade of the present invention;

[0034] Figure 2 It is a structural diagram of the present invention in a static state;

[0035] Figure 3 This is a flow chart of measuring a single 360-degree spiral blade according to the present invention;

[0036] Numbers in the figure: 1 single-piece 360-degree spiral blade; 2 support rod; 3 base; 4 ultrasonic probe. DETAILED DESCRIPTION

[0037] In this embodiment, Figure 2As shown, the mechanical Doppler signal generating device based on a single 360-degree spiral blade is a device that can maintain a long-term uniform motion and generate a mechanical Doppler signal with adjustable speed. The device can convert the angular velocity into a linear velocity that is easy to measure by an ultrasonic Doppler velocity measurement system, aiming to simplify the existing measurement method while improving the measurement accuracy and measurement speed; specifically, the device mainly includes: a single 360-degree spiral blade 1, a support rod 2, a base 3, and an ultrasonic probe 4;

[0038] A single 360-degree spiral blade 1 is arranged on the base 3 through the support rod 2, and the single 360-degree spiral blade 1 is driven by a motor to rotate;

[0039] An ultrasonic probe 4 is arranged in front of the fan surface of the single 360-degree spiral blade 1 for transmitting and receiving ultrasonic signals. The ultrasonic probe has two main working modes, CW (continuous wave) mode and PW (pulse wave) mode, which can transmit continuous wave signals and pulse wave signals respectively.

[0040] In this embodiment, a speed measurement method of a mechanical Doppler signal generating device of a single 360-degree spiral blade is performed according to the following steps:

[0041] Step 1: Use a motor to control the single 360-degree spiral blade 1 to rotate, and after the speed of the single 360-degree spiral blade 1 is stable, use an ultrasonic probe 4 to transmit a frequency of Ultrasonic signal;

[0042] Step 2: According to the Doppler effect, the single 360-degree spiral blade 1 receives a frequency of After the ultrasonic signal is generated, the frequency is Assuming that the moving direction is toward the ultrasonic probe 4, the frequency received by the single 360-degree spiral blade 1 is obtained by using formula (1): :

[0043] (1)

[0044] Formula (1) yields: is the propagation speed of ultrasound, is the relative motion speed between the single 360-degree spiral blade 1 and the ultrasonic probe 4, is the ultrasonic wavelength;

[0045] Step 3: According to the Doppler effect, the ultrasonic probe 4 receives the frequency reflected by the single 360-degree spiral blade 1. At this time, the 360-degree single-piece spiral fan blade 1 is equivalent to the wave source, and the ultrasonic probe 4 is equivalent to the receiver. The frequency of the doopler echo signal received by the ultrasonic probe 4 is obtained by using formula (2): :

[0046] (2)

[0047] Step 4: Use an ultrasonic Doppler velocity measurement system to analyze and process the doppler echo signal to obtain the rotation angular velocity of the single 360-degree spiral fan blade 1;

[0048] Step 4.1, Doppler shift is the Doppler frequency shift value, that is, the difference between the probe receiving frequency and the probe transmitting frequency, as shown in formula (3):

[0049] (3)

[0050] Step 4.2: Due to the measured The value is often much smaller than value, so the denominator The term can be omitted, so the Doppler frequency shift Measuring the linear velocity of a moving object The relationship is shown in formula (4):

[0051] (4)

[0052] Step 4.3: Figure 1 As shown, according to the structural characteristics of the single 360-degree spiral blade 1, each rotation is equivalent to a horizontal displacement , so every rotation Horizontal displacement As shown in formula (5):

[0053] (5)

[0054] Step 4.4: The angular velocity of a single 360-degree spiral blade 1 can be obtained. The measured line speed The relationship is shown in formula (6): (6)

[0055] In formula (6), is the pitch of a single 360-degree spiral blade 1, For rotation Time taken;

[0056] Step 4.5: Use equation (7) to obtain the angular velocity of the single 360-degree spiral blade 1: :

[0057] (7)

[0058] when When it is a positive value, it means that the single 360-degree spiral blade 1 rotates clockwise; when When it is a negative value, it means that the single 360-degree spiral blade 1 rotates counterclockwise.

[0059] Step 5: After the motor is used to adjust the single 360-degree spiral blade 1 to different rotation speeds, the process returns to step 1 and is executed sequentially, thereby realizing the speed measurement of the single 360-degree spiral blade 1 based on the Doppler effect.

[0060] Angular velocity measured by ultrasonic Doppler velocimetry system By comparing with the set rotation speed, the reliability of the ultrasonic Doppler speed measurement system can be verified.

Claims

1. A mechanical Doppler signal generating device based on a single 360-degree spiral blade, characterized in that: include: A single 360-degree spiral blade (1), a support rod (2), a base (3), and an ultrasonic probe (4); A single 360-degree spiral blade (1) is arranged on the base (3) via a support rod (2), and the single 360-degree spiral blade (1) is driven by a motor to rotate; An ultrasonic probe (4) is arranged directly in front of the fan surface of the 360-degree single-piece spiral blade (1) for transmitting and receiving ultrasonic signals.

2. A speed measurement method based on the mechanical Doppler signal generating device of the single-piece 360-degree spiral blade according to claim 1, characterized in that: The steps are as follows: Step 1: Use a motor to control the single 360-degree spiral blade (1) to rotate, and after the speed of the single 360-degree spiral blade (1) is stable, use an ultrasonic probe (4) to transmit a frequency of Ultrasonic signal; Step 2: According to the Doppler effect, the single 360-degree spiral blade (1) receives a frequency of After the ultrasonic signal is generated, the frequency is The echo signal; Step 3: According to the Doppler effect, the ultrasonic probe (4) receives the frequency reflected by the single 360-degree spiral blade (1) as The doopler echo signal; Step 4, analyzing and processing the doopler echo signal to obtain the rotational angular velocity of the single 360-degree spiral fan blade (1); Step 4.1: Calculate the Doppler shift using equation (1): : (1) Step 4.2: Use equation (2) to construct the Doppler frequency shift Linear speed with single 360 ​​degree spiral blade (1) The relationship is: (2) In formula (2), is the propagation speed of ultrasonic wave; Step 4.3: Use formula (3) to calculate the rotation speed of a single 360-degree spiral blade (1) Horizontal displacement : (3) In formula (3), is the pitch of a single 360-degree spiral blade (1); is the rotation angle of a single 360-degree spiral blade (1); Step 4.4: Use equation (4) to construct the angular velocity of a single 360-degree spiral blade (1): With line speed The relationship between: (4) In formula (4), A single spiral blade (1) that rotates 360 degrees Time taken; Step 4.5: Use formula (5) to obtain the angular velocity of the single 360-degree spiral blade (1): : (5) Step 5: After the motor is used to adjust the single 360-degree spiral blade (1) to different rotation speeds, the process returns to step 1 and is executed sequentially, thereby realizing the speed measurement of the single 360-degree spiral blade (1) based on the Doppler effect.

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